| 1. |
- Hertz, Hans M., et al.
(författare)
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Laboratory x-ray micro imaging : Sources, optics, systems and applications
- 2009
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 186
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Tidskriftsartikel (refereegranskat)abstract
- We summarize the recent progress in laboratory-scale soft and hard x-ray micro imaging in Stockholm. Our soft x-ray work is based on liquid-jet laser-plasma sources which are combined with diffractive and multilayer optics to form laboratory x-ray microscopes. In the hard x-ray regime the imaging is based on a liquid-metal-jet electron-impact source which provides the necessary coherence to allow phase-contrast imaging with high fidelity.
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| 2. |
- Hansson, B. A. M., et al.
(författare)
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Liquid-xenon-jet LPP source
- 2006
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Ingår i: EUV Sources for Lithography. - : SPIE - International Society for Optical Engineering. - 9780819480712 ; , s. 619-647
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Tuohimaa, Tomi, et al.
(författare)
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A microfocus x-ray source based on a nonmetal liquid-jet anode
- 2008
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 92:23, s. 233509-1-233509-3
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate stable operation of a nonmetallic anode in an electron-impact x-ray source. A high-brightness electron beam is focused on a similar to 70 m/s speed, similar to 10 mu m diameter methanol jet producing stable x-ray emission with peak spectral brightness at similar to 5.4 x 10(5) photons/(s x mu m(2) x sr x 0.1% BW). The jet is fully evaporated in the interaction point. The shape of a simulated spectrum using Monte Carlo methods shows good agreement with experimental data, and the theoretical brightness values give an upper limit for the achievable x-ray emission from jets with very high velocities. Using this anode concept, all compounds and elements found in liquid form are potentially usable for x-ray generation.
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| 4. |
- Vogt, Ulrich, et al.
(författare)
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Towards Soft X-Ray Phase-Sensitive Imaging with Diffractive Optical Elements
- 2006
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Ingår i: Proc. 8th International Conference X-ray Microscopy. ; , s. 91-93
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Konferensbidrag (refereegranskat)abstract
- In this contribution we present the first diffractive optical elements for soft x-ray differential interference contrast microscopy.Due to an improved calculation method the nanofabrication accuracy of these optics is the same as for comparable normal zoneplate optics with the same outermost zone width. Different diffractive optical elements were fabricated with outermost zone widthof 100 nm, different spot separation directions and different phase relations between the two spots. The optics were successfullyused in experiments both at the synchrotron radiation based TWINMIC microscope and at the Stockholm compact liquid-nitrogenlaser-plasma source based microscope.
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| 5. |
- Wiklund, Martin, et al.
(författare)
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Ultrasonic standing wave manipulation technology integrated into a dielectrophoretic chip
- 2006
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 6:12, s. 1537-1544
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Tidskriftsartikel (refereegranskat)abstract
- Several cell-based biological applications in microfluidic systems require simultaneous high-throughput and individual handling of cells or other bioparticles. Available chip-based tools for contactless manipulation are designed for either high-precision handling of individual particles, or high-throughput handling of ensembles of particles. In order to simultaneously perform both, we have combined two manipulation technologies based on ultrasonic standing waves (USWs) and dielectrophoresis (DEP) in a microfluidic chip. The principle is based on the competition between long-range ultrasonic forces, short-range dielcctrophoretic forces and viscous drag forces from the fluid flow. The ultrasound is coupled into the microchannel resonator by an external transducer with a refractive element placed on top of the chip, thereby allowing transmission light microscopy to continuously monitor the biological process. The DEP manipulation is generated by an electric field between co-planar microelectrodes placed on the bottom surface of the fluid channel. We demonstrate flexible and gentle elementary manipulation functions by the use of USWs and linear or curved DEP deflector elements that can be used in high-throughput biotechnology applications of individual cells.
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| 6. |
- Bertilson, Michael C., et al.
(författare)
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Zone plate efficiency measurements with a laser-plasma source
- 2007
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Ingår i: Advances in X-Ray/EUV Optics and Components II. - : SPIE. - 9780819468536 ; , s. F7050-F7050
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Konferensbidrag (refereegranskat)abstract
- We demonstrate a compact instrument for rapid and accurate measurements of the absolute and local efficiency of soft x-ray zone plates in the water window [M. Bertilson, et al, Rev. Sci. Instrum 78, 026103 (2007)]. The arrangement is based on a new single-line lambda = 2.88 nm liquid-nitrogen-jet laser-plasma source. The versatility of the instrument enables micro and condenser zone plates with focal lengths in the range from similar to 200 mu m to similar to 100 mm to be measured. We demonstrate an accurate local efficiency map of a in-house fabricated micro zone plate. Furthermore, we show how this compact instrument allows rapid feedback to the fabrication process which is important for future improvements.
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| 7. |
- Bertilson, Michael, et al.
(författare)
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Compact high-resolution differential interference contrast soft x-ray microscopy
- 2008
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 92:064104
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate high-resolution x-ray differential interference contrast (DIC) in a compact soft x-ray microscope. Phase contrast imaging is enabled by the use of a diffractive optical element objective which is matched to the coherence conditions in the microscope setup. The performance of the diffractive optical element objective is evaluated in comparison with a normal zone plate by imaging of a nickel siemens star pattern and linear grating test objects. Images obtained with the DIC optic exhibit typical DIC enhancement in addition to the normal absorption contrast. Contrast transfer functions based on modulation measurements in the obtained images show that the DIC optic gives a significant increase in contrast without reducing the spatial resolution. The phase contrast operation mode now available for our compact soft x-ray microscope will be a useful tool for future studies of samples with low absorption contrast.
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| 8. |
- Bertilson, Michael, et al.
(författare)
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High-resolution computed tomography with a compact soft x-ray microscope
- 2009
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Ingår i: Optics Express. - 1094-4087. ; 17:13, s. 11057-11065
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Tidskriftsartikel (refereegranskat)abstract
- Computed tomography based on high-resolution soft x-ray microscopy utilizes the natural contrast for biological specimens provided by the water window (lambda = 2.4 - 4.4 nm) and the high resolving power of zone plate objectives. It is capable of revealing the 3D structure of biological specimens at sub-visible-microscopic resolution. To date, the technique has only been available at synchrotron-based microscopes, which limits the researchers access. In the present paper we demonstrate high-resolution soft x-ray tomography with a laboratory zone-plate-based soft x-ray microscope. The specimen, a diatom mounted on a glass capillary, was reconstructed from a tilt series of 53 images covering 180 using a filtered back projection algorithm. The resolution of the tomogram was estimated to a half period of 140 nm using a differential-phase-residual method. Cryo-fixation, increased source brightness and extended-depth-of-focus objectives are important for pushing the resolution of compact systems for biological samples.
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| 9. |
- Hertz, Hans M., et al.
(författare)
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Laboratory X-ray micro- and nano-imaging
- 2009
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Ingår i: Frontiers in Optics (FiO) 2009. - Washington, D.C. : Optical Society of America. - 9781557528780
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Konferensbidrag (refereegranskat)abstract
- We summarize recent progress in laboratory x-ray imaging systems based on compact high-brightness liquid-jet sources, including <25 nm soft x-ray zone-plate microscopy and <10 μm (lens-free) hard x-ray phase-contrast imaging.
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| 10. |
- Holmberg, Anders, et al.
(författare)
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Controlled electroplating for high-aspect-ratio zone plate fabrication
- 2006
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Ingår i: Journal of Vacuum Science & Technology B. - : American Vacuum Society. - 1071-1023 .- 1520-8567. ; 24:6, s. 2592-2596
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Tidskriftsartikel (refereegranskat)abstract
- The authors report a method for monitoring, control, and end-point detection of electroplating in nanostructures. The method is demonstrated on nickel plating into polymer molds, which is an important process in the fabrication of soft x-ray zone-plate diffractive optics. The lack of reproducibility presently limits the achievable nickel aspect ratio and, thus, reduces the zone-plate diffraction efficiency. The reported method provides reproducible plating via real-time control of the plating rate. It combines in situ light transmission measurements with current measurements to determine the thickness of the growing layer. The accuracy of the thickness prediction was better than ±4% (1) for 100–300 nm nickel layers. Furthermore, a slight change in the light transmission signal indicates when a gratinglike zone-plate structure is slightly overplated and the plating should be stopped. This end-point detection provides the optimal filling of high-aspect-ratio molds for improved diffraction efficiency.
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